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Biomedical subjects

M Lux

Publications and source records attributed to M Lux.

At least 19 recordsLinked to original sources
PubMed2005

Gender differences in 24-hour urinary diaries of asymptomatic North American adults.

PURPOSE: Two previously published studies from our center have described the urinary habits of asymptomatic men (284) and women (300) as revealed by 24-hour urinary diaries. Those gender specific studies found that urinary diary variables are affected by age and race. By comparing the data from those studies we determined the effect of gender on voiding habits. MATERIALS AND METHODS: In this secondary analysis we matched each female urinary diary to that of a male of similar age and race. Diary variables were compared using paired sign tests with results considered significant at the 5% level. RESULTS: A total of 141 matched pairs were studied. The population age ranged from 18 to 68 years and was racially diverse (56% black, 31% white, 7% Hispanic and 6% Asian). Men had higher total fluid intake and mean voided volume than women (p <0.001 and 0.04, respectively). Women voided more frequently than men (p = 0.006) and had more voids per liter of fluid intake (p <0.001). No gender differences were found for body mass index, nighttime or daytime diuresis rates, total urine volume, maximum voided volume or rates of nocturia. CONCLUSIONS: This analysis suggests that there are significant gender effects on 24-hour diary variables, with females tending to void more often and at lower mean volumes. The results of our study may be useful in the design of research studies or for patient counseling.

Adolescent↗
PubMed2000

[Breast cancer: assessment of individual risk and possibilities for prevention].

Today, prevention of breast cancer (BC) is a great demand. The exact estimation of the individual BC-risk is a prerequisite for the participation on early cancer detection or the use of preventive medication or surgery. Various models for risk assessment of BC development or the presence of a predisposing mutation (i.e. BRCA1 or BRCA2) are used, but the statistical individual risk assessment still remains uncertain. Calculating an elevated risk or detection of a predisposing mutation leads to the recommendation of preventive measurements. After detailed assessment, prophylactic bilateral mastectomy is an option to consider for mutation carriers. For women with low BC-risk, chemoprevention can be discussed. Chemoprevention with tamoxifen (TAM)--indirectly supported by BC data from the raloxifen (RLX) prevention trial for osteoporosis and cardio-vascular disease--points to the right direction. Results from the three published TAM prevention trials are variable. Life time risk, age and life style have to be considered in the adapted individual risk-benefit assessment. The lack of long term risk data for chemoprevention and the effect on survival are arguments contra the routine use of TAM as a chemopreventive agent.

Anticarcinogenic Agents↗
PubMed1999

Half of Saccharomyces cerevisiae carbamoyl phosphate synthetase produces and channels carbamoyl phosphate to the fused aspartate transcarbamoylase domain.

The first two steps of the de novo pyrimidine biosynthetic pathway in Saccharomyces cerevisiae are catalyzed by a 240-kDa bifunctional protein encoded by the ura2 locus. Although the constituent enzymes, carbamoyl phosphate synthetase (CPSase) and aspartate transcarbamoylase (ATCase) function independently, there are interdomain interactions uniquely associated with the multifunctional protein. Both CPSase and ATCase are feedback inhibited by UTP. Moreover, the intermediate carbamoyl phosphate is channeled from the CPSase domain where it is synthesized to the ATCase domain where it is used in the synthesis of carbamoyl aspartate. To better understand these processes, a recombinant plasmid was constructed that encoded a protein lacking the amidotransferase domain and the amino half of the CPSase domain, a 100-kDa chain segment. The truncated complex consisted of the carboxyl half of the CPSase domain fused to the ATCase domain via the pDHO domain, an inactive dihydroorotase homologue that bridges the two functional domains in the native molecule. Not only was the "half CPSase" catalytically active, but it was regulated by UTP to the same extent as the parent molecule. In contrast, the ATCase domain was no longer sensitive to the nucleotide, suggesting that the two catalytic activities are controlled by distinct mechanisms. Most remarkably, isotope dilution and transient time measurements showed that the truncated complex channels carbamoyl phosphate. The overall CPSase-ATCase reaction is much less sensitive than the parent molecule to the ATCase bisubstrate analogue, N-phosphonacetyl-L-aspartate (PALA), providing evidence that the endogenously produced carbamoyl phosphate is sequestered and channeled to the ATCase active site.

Aspartate Carbamoyltransferase↗
PubMed1998

Perfect subjects: race, tuberculosis, and the Qu'Appelle BCG Vaccine Trial.

This article examines how Native children of the Qu'Appelle reserves in southern Saskatchewan became the subjects of a trial of the BCG vaccine for tuberculosis in 1933. Race and theories of racial evolution were referred to in the construction of the Native people as "primitives" and the reserves as disease menaces to the surrounding communities. Dr. R.G. Ferguson, medical superintendent of the nearby Qu'Appelle Sanatorium conducted the trial in order to prove that BCG could provide resistance to tuberculosis even among the "less evolved races." While BCG afforded some protection against tuberculosis, nearly one-fifth of the children in the trial died from diseases of poverty, gastroenteritis and pneumonia, as a result of the lethal living conditions on the reserves.

BCG Vaccine↗
PubMed1994

Heart rate variability as a prognostic tool in cardiology. A contribution to the problem from a theoretical point of view.

BACKGROUND: Recent clinical studies have proposed standard deviation of heart rate as a diagnostic tool for the outcome of cardiac infarction. Mathematical analysis of heart rate variability shows that heart rate is influenced by different frequency components derived from different parts of the autonomous nervous system. In the experimental part of this study, we investigated the possibility of calculating a variable describing the parasympathetic branch of the autonomous nervous system exclusively. METHODS AND RESULTS: In 60 healthy volunteers, heart rate was measured to 1 millisecond during two different conditions: 5 minutes of rest, and 5 minutes of intermittent handgrip dynamometry; the latter is known to increase sympathetic arousal selectively. Heart rate was found to be lower at rest (65.9 +/- 9.7 beats per minute) than during dynamometry (72.8 +/- 10.4 beats per minute, P < .001). Respiratory sinus arrhythmia (RSA) calculated from the mean absolute differences between successive heart beats showed no significant change (3.01 +/- 1.62 beats per minute at rest versus 2.97 +/- 1.30 beats per minute during dynamometry). In contrast, standard deviation increased from 5.19 +/- 1.98 to 9.22 +/- 3.56 beats per minute (P < .001). CONCLUSIONS: It can be concluded from these data as well as from other plots presented in this article that RSA is a measure of the parasympathetic vagal tone, whereas standard deviation is increased by both sympathetic and parasympathetic arousal. Clinical evidence and data from physiological experiments are presented to show that a selective measure of vagal tone like RSA may offer advantages over standard deviation as a prognostic tool in cardiology.

Autonomic Nervous System↗
PubMed1992

Isolation of Der pI, the Dermatophagoides pteronyssinus major mite allergen, from a crude mite culture extract, purification by ion-chromatography, and comparison between the material obtained and a cDNA-coded Der pI.

A high degree of purity is a prerequisite for an allergen preparation to be suitable for clinical diagnosis and therapy. A pure allergen can easily be obtained from a crude mite culture extract by using an immunosorbent prepared with highly specific monoclonal antibodies or from a cDNA-coded material. However, up to now none of these methods has been performed on a process scale. Here large-scale purification is defined as a process in which a crude Dermatophagoides pteronyssinus mite culture extract is essentially fractionated by acetone and ammonium sulphate precipitations followed by anion-exchange high-performance liquid chromatography. A high yield of a very pure Der pI allergen is obtained during the first isocratic run, as shown by sodium dodecylsulphate-polyacrylamide gel electrophoresis, capillary electrophoresis, chromatofocusing and a two site monoclonal antibody enzyme-linked immunosorbent assay. Microsequencing revealed that the 25-residue sequence obtained is entirely in agreement with the sequence derived from the cDNA of Der pI.

Allergens↗
PubMed1991

Isolation and purification of cat albumin from cat serum by copper ion affinity chromatography: further analysis of its primary structure.

Proteins, regardless of their origin, have to be highly purified, particularly from the immunochemical point of view, if they are to be used to study their allergenicity. It is shown that cat albumin, a highly potent allergen for cat-sensitive humans, can be isolated and purified from cat serum using immobilized metal ion affinity chromatography (copper ions) instead of a salting-out process or precipitation with alcohol, techniques generally used for the preparation of serum proteins. During the process described, immunoglobulins are concomitantly isolated in a relatively pure form. Cat albumin amino acid composition and sequence were analysed after an ultimate purification by ion-exchange chromatography. The highest homology (greater than 80%) was found with the rat serum albumin.

Albumins↗
PubMed1985

Muscle tissue oxygen pressure in patients with arterial occlusive disease.

Oxygen pressure histograms were determined with the multiwire surface electrode from the gastrocnemius muscle in patients with arterial occlusive disease and compared with those of healthy volunteers. Seven out of 22 patients had normally distributed histograms like volunteers, but the mean PO2 values were lower than the total mean value of the volunteers. Fifteen patients showed scattered histograms with dominating low PO2 values. Ten out of 11 patients suffering from diabetes mellitus had scattered histograms. When perfusion pressure was impaired by elevating the leg or the musculature was stressed in 7 patients the histograms' form of all these patients changed significantly. Median PO2 fell in all cases with clinically decompensated occlusive disease. Percutaneous transluminal angioplasty of an occlusion of the superficial femoral artery led to a significant shift of the histogram to higher PO2 values. The scattered histograms of patients suffering from arterial occlusive disease are thought to be caused by an inhomogeneous blood flow probably induced by the closure of arterioles.

Angioplasty, Balloon↗
PubMed1983

Comparison of antigenic and allergenic composition of two partially purified extracts from Dermatophagoïdes farinae and Dermatophagoïdes pteronyssinus mite cultures.

Dermatophagoïdes farinae (Df 80d) and Dermatophagoïdes pteronyssinus (Dp 80d) extracts were analyzed for their antigenic and allergenic composition by means of crossed immunoelectrophoresis (CIE) and crossed radioimmunoelectrophoresis (CRIE). By CIE, 11 antigens could be numbered in Df 80d (Df 1 to Df 11) and seven antigens in Dp 80d (Dp 1 to Dp 7). This technique allowed us also to define antigens with common as well as specific parts for the two mite species. Among the antigens of D. farinae and D. pteronyssinus, only the antigen corresponding to Df 5 and Dp 5 seems to bear common epitopes to the two mite species, whereas Df 6 and Dp 4 appear to bear, respectively, specific epitopes of each species. Moreover, Df 11 appears to bear specific epitopes of D. farinae, although it shows a partial identity with Dp 7. By CRIE, on 20 mite-sensitive patients' sera, we identified, for each mite extract, the allergens responsive to human specific IgE. The allergograms show that the majority of mite-sensitive patients react with Df 11 and Df 6 and with Dp 7 and Dp 4. Thus, these antigens can be considered as major allergens. The minor allergens were also identified. None of these antigens was recognized by the control sera. Moreover, we observed that for one antigen (antigen 5) there exist antigenic determinants common to the two species of mites toward the rabbit serum and specific allergenic determinants to the human IgE response. A significant correlation was found between the specific IgE binding in CRIE and in RAST (Spearman coefficient: "rs" = 0.61 p less than 0.01 for Df; "rs" = 0.78 p less than 0.01 for Dp).

Allergens↗
PubMed1983

[Internal intestinal splinting with a soluble tube for the prevention of recurrent adhesion ileus].

An absorbable, non-toxic, easy gliding, cross-linked gelatine tube has been developed to prevent and to treat chronical adhesion ileus. The tube is patterned upon the interior intestinal splinting with long tubes. By doing a small enterotomy it was possible to splint the whole intestine in pigs or endangered parts within a few minutes. The flexible gelatine tube does not kink and is melting off from the surface. It prevents the intestine from kinking and does not cause any lesions even on previously damaged intestinal walls. Possible complications seen by insertion and extraction of conventional tubes were not observed.

Animals↗
PubMed1982

[Light microscopic and histochemical findings on the mouse lung after neutron and 60 cobalt gamma-irradiation].

The morphological changes on lungs of thorax irradiated mice, receiving a single dose of fast neutron and 60 cobalt radiation were investigated. Lungs were studied by histological and histochemical methods 2 weeks up to 10 months. Harvest changes were found after a time of 4-8 weeks. With histochemical methods more detailed damages are seen in contrast to routine histology. Two weeks post irradiation disturbances of phospholipid synthesis in alveolar epithelium cells of type II (AEC II) are found. Impairment of capillary endothelial cells are indicated by decreased activity of adenosine triphosphatase. Increased activity of beta-glucuronidase is seen in damaged bronchial epithelium.

Acid Phosphatase↗
PubMed1981

Antigens and allergens in Dermatophagoïdes farinae mite. I. Immunochemical and physicochemical study of two allergenic fractions from a partially-purified Dermatophagoïdes farinae mite extract.

The fractionation of a partially-purified extract of Dermatophagoïdes farinae mite culture has been undertaken by gel filtration. Two fractions were isolated. One, P25, is a protein-rich fraction with mol. wt about 25,000. The other, GP8, is a polysaccharide-rich fraction with mol. wt around 8,000. By crossed immunoelectrophoresis, we detected eleven antigens in the partially-purified dialysed D. farinae extract (Df 80d) as well as in P25 fraction. One of them, ag 11, seems the most important allergen since in crossed-radio immunoelectrophoresis experiments it displays the faster radiostaining, implying that it binds the greatest part of the mite-specific IgE present in a pool of sera from mite-sensitive patients. By crossed-line immunoelectrophoresis, we demonstrated the absence of ag 11 in GP8, in which only ag 5 and ag 6 were identifiable. By radioalloergosorbent tests (RAST), it was found that P25- and GP8- coated paper discs can fix specific IgE induced in the majority of D. farinae sensitive patients. Defining a 'major allergen' as an allergen to which the majority of sensitive patients develop specific IgE, both P25 and GP8 do appear to contain at least one major allergen. By RAST inhibition method, using Df 80d as a solid phase, the allergenic activity of P25 appeared as slightly higher than that of Df 80d, whereas GP8 displayed a very weak inhibitor capacity. Thus, the allergic specificity of GP8 differs from that of Df 80d or P25.

Allergens↗